Extendable conveyor with additional boom section

ABSTRACT

An outer extendable boom or extension is implemented on an extendable conveyor of conventional design, which includes at least two extendable units, each of which is nested within the next inwardly positioned unit and adjustably positioned between an extended position and a retracted position. The outer boom includes a pair of opposite side members which extend within an outer conventional extendable unit and a conveying surface. A support system is provided to support the outer boom as it extends and retracts within the outer extendable unit. A forward support member of the support system is laterally aligned with the side members and a cantilever support member is vertically spaced from a rearward end of the side members, such that a reduced range in width and a reduced range in height of the extendable units may be achieved. Accordingly, the outer boom or extension provides a substantial increase in the extendable reach of the conveyor assembly, while avoiding any adverse affect on the width of the conveying surfaces and the height of the conveying surface associated with the base unit. The present invention also provides for an extendable attachment to be implemented within a pre-existing conventional extendable conveyor assembly.

BACKGROUND OF THE INVENTION

This invention relates generally to conveyors and, more particularly, toextendable conveyors for loading products into, or unloading productsfrom, a truck trailer or the like.

Extendable conveyor units are typically implemented for loading andunloading truck trailers or the like in order to minimize the distancewhich the product being loaded or unloaded must be manually carried.Extendable conveyors in use today may have two, three or four extendableunits, or extensions, in order to achieve the desired extended lengthfor reaching a forward portion of the truck trailer, while stillproviding a relatively compact conveyor when it is retracted on theloading dock.

In order to provide an extendable conveyor which may retract into arelatively compact position on the loading dock, extendable conveyorstypically include a base unit which is anchored to a warehouse orloading dock floor and one or more extendable units which are nestedwithin the base unit and within each of the other inwardly positionedextendable units. The base unit and the extendable units may includehorizontal support channels in order to guide the outwardly positionedextendable units and to bear the cantilever loading of the extendableunits as they extend therefrom. Because the extendable units are nestedwithin one another, the number of extendable units are typicallylimited, since additional units would either excessively limit the widthof the outermost unit or result in a conveyor which is taller andrequires a greater amount of floor space.

Generally, it is desirable to maximize the ratio of the width of theconveyor belt to the overall width of the base unit, such that there isa minimal difference between the two dimensions. In order to provide alarger space on which to place the cargo being loaded or unloaded, it isalso important to maximize the width of the conveyor belt and outerconveying surface. Because each extendable unit is nested within theother inwardly positioned units, the width of the outermost nested unitswill be less than the width of the base structure and the inner units.Accordingly, additional extensions may be excessively narrow and may notaccommodate the cargo on their conveying surface. Although such aconcern may be resolved by including wider inner units and a wider baseunit to accommodate a wider outermost extension, this is alsoundesirable, since the greater width of the base unit interferes withthe floor space of the warehouse.

An additional concern with increasing the number of extendable units ofthe conveyor is that each unit requires a substantial amount of verticalspace within the next inwardly positioned unit. This further results inthe conveying surface of the base structure being at a greater height inorder to accommodate each additional extendable unit. Such a design maynot be feasible, since the conveying surface may have to accommodate analready existing supply or take-away conveyor which is installed at thewarehouse or loading dock.

It is also generally desirable to maximize the ratio of the fullyextended conveyor to the retracted length of the conveyor, in order tominimize the intrusion of the conveyor in the warehouse when it is notin use, while still providing a maximum extended length to reach intothe truck trailers. Accordingly, extendable conveyors with longer boomsor extendable units may not be desirable, since such a design would alsorequire substantially more floor space in its retracted position whenthe conveyor is not in use. The longer, retracted units would theninterfere with floor space that is required for people or machinery tomove about within the warehouse.

Other concerns arise with respect to existing extendable conveyors inthat such conveyors may be unable to extend a desired length due to theimplementation of longer delivery trucks or other restrictions which mayprevent the trucks from backing all the way up to the dock on which theextendable conveyor is mounted. Extensions have been proposed which maybe attachable to an existing two, three or four unit extendable conveyorin order to achieve a greater length without having to replace theentire conveyor. Some extensions may be mounted on an outermost end ofthe outer extendable unit in order to provide an additional length tothe extendable conveyor. However, such extensions do not nest within theinwardly positioned units when retracted and may not retract completelywith the extendable conveyor. Such extensions may thus adversely affectthe floor space requirements for the conveyor in the warehouse.Furthermore, these proposed extensions require a separate power sourceto operate a separate drive system for driving a separate conveyor beltalong the additional extension. These separate conveying belts aretypically of a reduced width with respect to the conveying portions andbelt of the existing conveyor in order to allow the additional unit torest upon the existing conveyor.

Therefore, there is a need in the art for an extendable conveyor whichmay extend farther into a truck trailer, without adversely affecting thewidth of the conveying surface or the floor space taken up by theextendable conveyor when it is retracted. Furthermore, the overallheight of the conveying surface of the base structure should not beaffected, in order to implement the conveyor adjacent to alreadyexisting supply or take-away conveyors in place at the warehouse orloading dock. Furthermore, there should be provided the capability toretro fit existing extendable conveyors with extensions in a mannerwhich does not require a narrower conveying surface and which retractsfully with respect to a base unit.

SUMMARY OF THE INVENTION

The present invention is intended to provide an extendable conveyorwhich may extend farther into a truck trailer or the like overpreviously proposed conveyors, without adversely affecting the floorspace required for such a conveyor and the retracted length and/or widthof the conveying surface of the conveyor.

According to an aspect of the present invention, an extendable conveyorfor conveying articles comprises a base structure, at least oneextendable unit adjustably positioned between a retracted position andan extended position relative to the base structure, an extendable boomat least partially nested within the extendable unit and a supportsystem for the extendable boom. The extendable unit has an upperportion, at least a portion of which defines a first conveying surface.The extendable boom is adjustably positionable between a retracted andextended position relative to the extendable unit. The extendable boomdefines a second conveying surface. The support system includes at leastone forward support member and a cantilever support member. Thecantilever support member engages the upper portion of the extendableunit to cantileverly support the extendable boom relative to theextendable unit. The forward support member engages and supports theextendable boom and allows a greater width of the second conveyingsurface relative to a width of the first conveying surface.

In one form, the extendable boom comprises a pair of side members whichare insertable into the extendable unit and a conveying mechanism whichis pivotally attached to a forward end of the side members and extendsover top of the extendable units. The forward support member isrotatably attached to the extendable unit such that a lower surface ofthe side members engages the forward support member for rolling contacttherewith.

In another form, the extendable boom nests substantially within theforward extendable unit. The forward support members comprise a rollercarriage which provides rolling engagement between a lower track alongopposite sidewalls of the forward extendable unit and a lower portion ofa pair of opposite side members of the extendable boom. The rollercarriage provides support for the extendable boom relative to theforward extendable unit by moving forwardly along the forward extendableunit as the extendable boom is extended and rearwardly along the forwardextendable unit as the extendable boom is retracted.

According to another aspect of the present invention, an extendableconveyor for conveying articles comprises a base structure, at least oneextendable unit adjustably positioned between a retracted position andan extended position relative to the base structure and an extendableboom which is at least partially nested within the extendable unit. Theextendable boom is adjustably positioned between a retracted positionand an extended position relative to the extendable unit. The extendableunit has a first conveying surface which has a first width. Theextendable boom is operable to extend outwardly from the extendable unitsuch that the extendable boom is cantileverly supported by theextendable unit. The extendable boom has a second conveying surfacewhich has a second width. The second width is at least as great as thefirst width of the first conveying surface.

According to yet another aspect of the present invention, an extendableconveyor comprises a base structure, at least one extendable unitadjustably positioned between a retracted position and an extendedposition relative to the base structure, an extendable boom whichextends and retracts within the extendable unit and a support system forthe extendable boom. The extendable unit has a first conveying surfaceand the extendable boom has a second conveying surface. The supportsystem includes a cantilever support roller and a roller carriage. Theroller carriage includes at least one roller which is operable to rollrelative to the extendable unit and the extendable boom such that theroller carriage moves outwardly relative to the extendable unit as theextendable boom moves outwardly relative to the roller carriage and theextendable unit. The extendable boom moves approximately twice thedistance that the roller carriage moves relative to the extendable unit.

These and other objects, advantages, purposes and features of thisinvention will become apparent upon review of the followingspecification in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation of an extendable conveyor according to anaspect of the present invention in a fully retracted position;

FIG. 2 is the same side elevation as that in FIG. 1, with the extendableconveyor in a partially extended position;

FIG. 3 is an enlarged view of the area designated III in FIG. 2;

FIG. 4 is the same enlarged view of FIG. 3 when the conveyor is in itsfully extended position;

FIG. 5 is a top plan view of the conveyor of FIG. 4;

FIG. 6 is an end view along the line VI—VI in FIG. 5;

FIG. 7 is the same view as FIG. 3 of an alternate embodiment of thepresent invention in a partially extended position;

FIG. 8 is a partial side elevation of another embodiment of the presentinvention in an extended position;

FIG. 9 is an enlarged view of the area designated IX in FIG. 8;

FIG. 10 is a top plan view of the conveyor in FIG. 9;

FIG. 11 is a sectional view taken along the line XI—XI in FIG. 9;

FIG. 12 is the same view as FIG. 9, with the outer extension in aretracted position;

FIG. 13 is a top plan view of the conveyor in FIG. 12;

FIG. 14 is a partial side elevation of another embodiment of the presentinvention in an extended position;

FIG. 15 is the same view as FIG. 14, with the outer extension in aretracted position; and

FIG. 16 is a sectional view taken along the line XVI—XVI in FIG. 15.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now specifically to the drawings, and the illustrativeembodiments depicted herein, an extendable conveyor 10 is supported on abase unit 12, which may be anchored to a floor 14 of a warehouse or thelike and may be adjacent to a supply or take-away conveyor 16 (FIG. 1).The adjustable conveyor 10 includes a plurality of extendable sectionsor units 15 and an outermost additional unit or boom 22, which areextendable outwardly or forwardly from base unit 12 for extending into atruck trailer 18 or the like to load and unload products into and outfrom truck trailer 18 (FIG. 2). As used herein, unless otherwise noted,the terms outwardly and forwardly are used to describe the directionwhich the extendable units 15 extend from the base unit, while the termsinwardly and rearwardly are used to describe the direction of travel ofthe extendable units as they are retracted toward the base unit.Preferably, base unit 12 and extendable units 15 are of the typedisclosed in commonly assigned U.S. Pat. No. 5,351,809 issued to Gilmoreet al. and U.S. Pat. No. 5,423,413 issued to Gilmore, the disclosures ofwhich are hereby incorporated herein by reference. Extendable conveyor10 may include one, two, three, four or more extendable units 15. Forexample, extendable conveyor 10 may include four extendable units 24,36, 34, and 32, and base unit 12 as shown in FIGS. 1 and 2, which defineboom, or additional extension, 22 engages the outer nested extendableunit 24 and is supported and guided therewithin by a support system 37.Support system 37 includes a cantilever support roller 64 and a forwardor outer support roller 60 on each side of extendable boom 22 to supportextendable boom 22 as it is extended and retracted relative to outerextendable unit 24. Extendable boom 22 further includes a conveyingportion 52, which may overlap or rest upon one or more of the conveyingportions 24 a, 36 a, 34 a, 32 a and 28 of the extendable conveyor 10.Preferably, the width of conveying portion 52 is at a substantiallysimilar width or may be wider than the width of the outermost nestedunit 24. Although shown and described herein as being implemented on aconveyor having four extendable units and a base unit, clearly theextendable boom may be implemented on a conveyor having more or lessunits, without affecting the scope of the present invention.

Because the inner nested extendable units of extendable conveyor 10 aredescribed in the Gilmore '809 and '413 patents, a detailed discussion ofthe extendable units will not be repeated herein. Suffice it to say,extendable conveyor 10 preferably comprises two or more extendableunits. As shown in FIGS. 1 and 2, extendable conveyor 10 may comprise arearward or inner or first extendable unit 32, a second extendable unit34, a third extendable unit 36 and a fourth or forward or outerextendable unit 24. Each of the extendable units 24, 36, 34 and 32 arenested within the next inwardly positioned unit and extend and retractin a known fashion by a drive motor 38 and a plurality of chains andsprockets or pulleys (not shown). Preferably, each extendable unit isextendable and retractable at twice the rate as the next inwardlypositioned unit, as is known in the art. As each extendable unit extendsoutwardly from the next inwardly positioned unit, a cantilever supportroller 42 rolls along and engages the next inwardly positioned unit inorder to provide a cantilever support to each extending unit, whileforward support rollers 39 support a forward end of each unit.

A continuous conveyor belt 40 is routed around multiple belt rollers 41positioned at each end of each extendable unit 24, 36, 34 and 32, and isdriven by a drive motor 44. Drive motor 44 functions to move the endlessconveyor belt 40 along the conveying portions 24 a, 36 a, 34 a, 32 a and28 of the extendable units 15 and base 12, respectively, in order tomove products along the extendable units between the truck trailer 18and take-away or supply conveyor 16. As is known in the art, the beltrouting allows belt 40 to be driven by motor 44 when extendable conveyor10 is either fully retracted (FIG. 1) or partially or fully extended,while retaining the proper tension on belt 40.

Base unit 12 may be supported above floor 14 by a rearward supportstructure 46 and a forward adjustable vertical support 48, whichfunctions to raise and lower the conveyor as it extends outward intotruck trailer 18 or the like. An electrical cable (not shown) may beinterconnected to drive motors 38 and 44 and adjustable vertical support48 and routed through the extendable units toward an outer or forwardend of extendable unit 24 for connection to a control panel or device,as discussed below. Preferably, the cable is routed around separatepulleys to maintain proper tension in the cable, as is disclosed in U.S.Patent 5,423,413, referenced above.

Each extendable unit 24, 36, 34, and 32 is nested within the nextinwardly positioned unit or base structure 12 (FIG. 6). Outer unit 24 isdefined by a pair of side walls 54 interconnected by an upper conveyingportion 24 a, such as a slider bed or other conveying surface. Each sidewall 54 is substantially C-shaped, having an upper, laterally inwardlyturned portion 54 b and a lower, laterally inwardly turned portion 54 d.Side walls 54 are further interconnected at their outer ends by an endplate 98. An outer belt roller 58 is rotatably mounted between a pair ofbrackets 56, which are secured to end plate 98 and extend rearwardlytherefrom. Belt roller 58 is rotatably mounted at outer end 24 b of unit24 to reverse belt 40 herearound as it is guided toward an inner roller80 of extendable boom 22 (FIGS. 3 and 4). Preferably, a pair ofapertures 55 are formed in end plate 98 for insertion of a pair of sidemembers 50 of boom 22 into extendable unit 24 between brackets 56 andtheir respective side walls 54.

Outer boom 22 includes a pair of opposite side members or support beams50, which insert into a space defined by outer extendable unit 24, andan upper conveying portion 52. Conveying portion 52 includes a pair ofopposite side walls 52 a which are interconnected along an upper end todefine an upper conveying surface 26. Conveying portion 52 is preferablypivotally interconnected to outer end 22 a of extendable boom 22 andextends inwardly over an upper surface of one or more of the extendableunits 24, 36, 34 and 32 as extendable conveyor 10 is moved between itsretracted and extended positions. A pair of rollers 76 may be includedat an inward end 52 a of conveying portion 52 to engage the conveyingportions 24 a, 36 a, 34 a, 32 a and 28 of the extendable conveyors 15and base 12 as boom 22 is extended and retracted relative to extendableconveyor 10.

Side members 50 of extendable boom 22 are preferably interconnected attheir outer end by a cross beam 71 to provide lateral stability to theboom 22. Outer or forward end 22 a of outer boom 22 is preferablydefined by a pair of side plates 70, each of which are secured to alaterally outer end 71 a of cross beam 71. Side plates 70 extendupwardly from their connection to cross beam 71, and are furtherinter-connected at their upper ends 70 a by a pivot axle 72 on whichconveying portion 52 is preferably pivotally secured. A control panel 90is preferably positioned on one or both of the side plates 70 to allowan operator to actuate drive motor 38 to extend or retract and to raiseor lower conveyor 10 and to actuate belt drive motor 44 from within thetruck trailer. Control panel 90 may further function to control a drivemotor 62 b to drive or rotate an inner support roller 62, therebyextending or retracting extendable boom 22 relative to extendable unit24. Control panel 90 may include a user operable lever to control theamount of extension as well as the height of the conveyor 10.Preferably, the lever is a joystick 90 a, but may be other controls,such as buttons or switches, without affecting the scope of the presentinvention.

Extendable boom 22 preferably further includes an electrical cable 92which interconnects control panel 90 with the conventional cable ofextendable conveyor 10. Because extendable boom 22 extends outwardly andretracts inwardly with respect to the next inwardly positioned unit 24,electrical cable 92 must be of a length great enough to allow for therelative movement between extension 22 and extendable unit 24.Preferably, electrical cable 92 is routed within a cable track or thelike, which may be unidirectionally flexible such that the cable forms areversing loop 94, as shown in FIGS. 1, 2 and 3. Accordingly, a lowerportion 92 a of cable 92 will remain substantially flat along extendableunit 24 while an upper portion 92 b rests substantially along and overtop of lower portion 92 a as side members 50 are extended and retractedwithin extendable unit 24. Such cable track is well known in the art andis commercially available from known sources. Because the track isunidirectionally flexible, the cable 92 will remain in its lateralorientation along the sideward portion of extendable unit 24. Thisprevents cable 92 from becoming entangled with support rollers 62 and/or64 or belt 40 as extendable conveyor 10 is extended or retracted, andfurther eliminates the need for an additional cable pulley or roller onextendable unit 24. Electrical cable 92 may be routed within or alongside one of the side members 50 to remain separated from belt 40 ascable 92 is routed toward control panel 90.

As extendable boom 22 is extended and retracted relative to extendableunit 24, support system 37 facilitates smooth translation of extendableboom 22, while cantileverly supporting the boom 22 as it extendsoutwardly from extendable unit 24. Cantilever support roller 64 ofsupport system 37 is rotatably mounted to a bracket 65 which extendsrearwardly from inner or rearward end 50 b of each side member 50.Cantilever roller 64 rolls along a lower surface 54 a of upper laterallyinwardly turned portion 54 b of side members 54. As boom 22 extendsoutwardly such that a majority of its weight is forward of supportroller 60, upper portion 54 b prevents upward motion of cantileverroller 64 and rearward end 50 b of support members 50, thereby providingcantilevered support of outer extendable boom 22 as it extends outwardlyfrom extendable unit 24. As shown in FIGS. 1-4 and 6, an upper portion64 a of cantilever support roller 64 extends upwardly and slightly abovea horizontal plane defined by an upper surface 50 d of side members 50.Cantilever support roller 64 extends a minimal amount above uppersurface 50 d to provide rolling engagement with surface 54 a of sides54, while allowing extendable boom 22 to be of a desired height forsupport and strength without adversely affecting the correspondingheight requirements for extendable unit 24. Although shown and describedas a pair of rollers, cantilever support 64 may otherwise be wheels, camfollowers or skid plates, without affecting the scope of the presentinvention.

Outer support roller 60 of support system 37 is preferably rotatablymounted near an outer end 54 e of each side 54 of extendable unit 24 andpositioned beneath side members 50 in order to guide and support sidemembers 50 as they extend and retract within extendable unit 24, as bestshown in FIGS. 3, 4 and 6. Although shown as a single roller mounted toextendable unit 24, outer support roller 60 may be a movable rollercarriage, which rolls between side members 50 of extendable boom 22 andsides 54 of extendable unit 24, as discussed below with respect toroller carriage 223 of extendable conveyor 200. Support system 37 mayfurther include inner or rearward support roller 62, which is rotatablymounted to side members 50 along a lower surface 50 a thereof. As sidemembers 50 extend and retract within extendable unit 24, outer supportrollers 60 are in rolling contact with underside 50 a of side members50, while inner support rollers 62 are in rolling contact with an uppersurface 54 c of lower inwardly turned portion 54 d of sides 54 ofextendable unit 24.

Preferably, inner and outer support rollers 62 and 60 are positioneddirectly beneath side members 50, such that a laterally outer side 62 aand 60 a of each is positioned substantially adjacent to or laterallyinwardly from a vertical plane defined by a laterally outer side 50 c ofside members 50. Because only a minimum space is required laterallyoutwardly from side members 50, this allows side members 50 ofextendable boom 22 to nest within outer extendable unit 24, while beingsubstantially laterally separated to provide a wider openingtherebetween. This further allows greater clearance between side members50 for conveyor belt 40, such that the addition of extendable boom 22has a minimal affect on the range of widths of conveyor belt 40 whichmay be implemented. Because a wider belt may be implemented withoutrequiring additional width of extendable unit 24 and thus of the otherunits and base unit 12 of conveyor 10, the present invention facilitatesmaximizing the ratio of the conveyor belt width to the width of theoverall extendable conveyor.

Preferably, inner support roller 62 is driven by a motor 62 b, such thatouter boom 22 is extendable and/or retractable independent of movementby extendable units 24, 36, 34 and 32. However, extendable boom 22 maybe extended and retracted in a similar manner as the extendable units24, 36, 34 and 32, as is known in the art. Alternatively, extendableattachment 22 may be manually movable relative to the next outermostextendable unit 24, without affecting the scope of the presentinvention.

As best shown in FIGS. 4 and 5, conveying portion 52 of extendable boomor attachment 22 extends rearwardly and upwardly from pivot axis 72 andpreferably bends at a belt roller 74 to extend further inwardly andsubstantially horizontally or slightly downwardly toward a conveyingsurface 24 a, 36 a, 34 a, 32 a or 28 of one of the extendable units 24,36, 34 or 32 or base unit 12, respectively. One or more support rollers76 may be rotatably mounted to inward end 52 a of conveying portion 52and spaced laterally apart for rolling contact with conveying surfaces24 a, 36 a, 34 a, 32 a and 28 on either side of conveyor belt 40 as theextendable units of conveyor 10 are extended and retracted. Preferably,a conveying ramp 78 may be implemented to interconnect an inward portion26 a of conveying surface 26 to one of the conveying surfaces of theextendable units and/or base unit 12. Ramp 78 is preferably formed witha plurality of laterally extending conveying rollers 78 a therealong,such that as a package or product is conveyed inwardly along conveyingsurface 26 of extension 22, the package may roll down ramp 78 due togravitational forces alone and onto the next conveying surface ofextendable conveyor 10. However, it is further envisioned that aseparately driven ramp assembly (not shown) or the like may beimplemented at inward end 26 a of conveying surface 26, such thatextendable conveyor 10 may be utilized as a loading conveyor as well asan unloading conveyor. The driven ramp may comprise a belt conveyor orpowered rollers, or any other known conveying means, without affectingthe scope of the present invention. Packages or product may then beconveyed outwardly along conveyor belt 40 on conveying surfaces 28, 32a, 34 a, 36 a and 24 a, and up the motorized ramp and onto conveyingsurface 26 of extendable boom 22.

Preferably, extendable boom 22 shares a common endless conveyor belt 40with base unit 12 and extendable units 24, 36, 34 and 32. As best shownin FIGS. 3 and 4, conveyor belt 40 may be reeved around belt roller 58of outer extendable unit 24 and further reeved around a belt roller 80at inward end 52 a of conveying portion 52 of extendable boom 22, suchthat belt 40 reverses around roller 80 and extends outwardly from beltroller 80 toward outer end 22 a of extension 22. Belt 40 may then beguided by a guide roller 82 to provide a curve in belt 40 such that belt40 extends downwardly and outwardly toward an outer belt roller 84. Byguiding belt 40 around guide roller 82, clearance is provided between abelt section (generally referenced as 40 a in FIG. 1) of belt 40 betweenrollers 58 and 80 and a belt section (generally referenced as 40 b inFIG. 1) of belt 40 between guide roller 82 and outer roller 84 whenextendable boom 22 is retracted.

Outer belt roller 84 is preferably positioned outwardly of pivot axis 72of conveying portion 52. Conveyor belt 40 reverses direction aroundouter roller 84 and travels inwardly along conveying surface 26 ofextendable boom 22 and is further guided around guide roller 74. Guideroller 74 facilitates curving of belt 40 substantially horizontally andslightly downwardly toward extendable conveyor 10, such that inwardportion 52 a of conveying portion 52 is substantially horizontal overconveying surface or portion 28 of base 12 when extendable boom 22 isretracted. At inward end 52 a of conveying portion 52, conveyor belt 40is curved in an S-shaped manner about a pair of belt rollers 86 and 88,such that belt 40 is guided inwardly from roller 88 along asubstantially horizontal path corresponding with the conveying portionor surface 24 a, 36 a, 34 a, 32 a, or 28 of the appropriate extendableunit or base unit upon which conveying portion 52 rests. The level ofbelt 40 as it travels rearward from roller 88 is adjusted to theappropriate conveying surface, because conveying portion 52 pivots asrollers 76 engage the conveying surfaces of the extendable unit or thebase unit, which are at slightly different heights. Accordingly, thecontinuous conveyor belt 40 is movable to convey products or packagesalong each of the conveying portions of extendable conveyor 10 andprovides a smooth transition to the next conveying portion regardless ofthe degree of extension or retraction of each individual extendable unitor extendable attachment of conveyor 10, since belt 40 remains taught inall orientations of extendable conveyor 10.

As shown in FIG. 1, when extendable conveyor 10 is in its fullyretracted position on base unit 12, conveying portion 52 of extendableboom 22 is pivoted about pivot axis 72 to its upward most position suchthat rollers 76 are on top of conveying surface 28 of base unit 12. Sidemembers 50 are retracted within extendable unit 24 such that thereversing loop or bend 94 of electrical cable 92 is immediately inwardof inward end 50 b of side members 50. As extendable conveyor 10 isextended outwardly by motorized drive 38, outermost extendable boom 22may be similarly driven outwardly, or may be driven by motor 62 b androllers 62. Rollers 76 correspondingly move outwardly with boom 22 androll along conveying surface 28 of base unit 12, onto conveying surface32 a of inner extendable unit 32, further onto conveying surface 34 a ofextendable unit 34, onto conveying surface 36 a of extendable unit 36and finally onto conveying surface 24 a of extendable unit 24 asextendable conveyor 10 is extended toward its fully extended positionshown in FIG. 4. As extendable conveyor 10 extends further outwardly,such that rollers 76 engage the next lower conveying surface, conveyingportion 52 pivots downwardly about pivot pin 72 in order to maintainrollers 76 and ramp 78 in rolling contact with each conveying surface.

Referring now to FIG. 7, an alternate embodiment is shown of anextendable conveyor 100, which also includes an outermost extendableboom 122 extending outwardly from an outer conventional extendable unit124. Extendable boom 122 is substantially similar to extendable, boom 22discussed above but includes a conveying portion 152 which has aseparate endless or continuous conveyor belt 153 routed thereon.Continuous belt 153 is preferably driven by a motorized pulley 187 whichdrives belt 153 along a pair of guide pulleys 182 a and 182 b, around anouter belt roller 184 and back over an upper guide roller 174 and alonga conveying surface 126 of extendable boom 122. A separate endlessconveyor belt 140 is routed and reeved about a plurality of pulleys andguide rollers 141 along and within a base unit (not shown) and one ormore extendable units, generally represented as extendable units 124,136 and 134 in FIG. 7. Endless belt 140 is routed and driven in aconventional manner along each of the extendable units of extendableconveyor 100. Extendable boom 122 facilitates minimal intrusion by theaddition of boom 122 onto an existing extendable conveyor, since theexisting endless conveyor belt need not be lengthened, or have anextension spliced therein, to be further routed around the rollers ofthe additional boom 122.

Although shown and described above as an extendable conveyor having anadditional outer boom associated therewith, the scope of the presentinvention includes providing an aftermarket extension which may beinstalled within an existing two, three or four unit extendableconveyor. The additional extendable boom or attachment 22 or 122 may beimplemented with an existing conveyor due to its minimal spacerequirements within the outer extendable unit of the conventionalconveyor. The attachment requires minimal space within the outerextendable unit due to the insertion of the pair of support members 50and cantilever rollers 64 within the outer extendable unit, while theconveying portion extends rearwardly above and outside of the outerextendable unit. In order to facilitate implementation of the extendableboom within the existing conveyor, a conventional control panel (notshown), which may be initially positioned along an outer end of anoutermost extendable unit, may be removed to provide clearance betweenthe mounting brackets 56 of the forward belt roller 58 and the sidewalls 54 of the extendable unit. Openings or apertures 55 may be formedin end plate 98 (FIG. 6) if necessary to allow side members 50 to beinserted therethrough and into the space provided within the outerextendable unit. A pair of outer support rollers 60 may be rotatablymounted at the outer end of the outer extendable unit, while a pair ofcantilever support rollers 64 may be provided on the side members of theextendable boom to support the boom as it extends and retracts withinthe outer extendable unit.

The electrical cable 92 may then be connected in a conventional mannerto the existing cable along the outer extendable unit to provide powerand control capabilities to the control panel 90 on the extendableattachment. Preferably, the cable 92 is routed along the side members ofthe extendable boom and reverses back toward the outer end of the outerextendable unit within a unidirectionally flexible section of cabletrack. An additional section of conveyor belt may be added or spliced toa continuous conveyor belt associated with the existing conveyor, suchthat the common continuous conveyor belt may be long enough to alsoroute within the conveying portion 52, as discussed above. Alternately,however, the existing endless or continuous belt 140 may continue to beutilized, while a separate endless belt is provided along the extendableattachment, as discussed above with respect to separate belt 153 ofconveying portion 152 of extension 122. Preferably, a separate drivemotor 62 b and rollers 62 may be implemented along with the additionalextension to drive rollers 62 in order to control extension andretraction of the extension within the outer extendable unit.Alternately, the additional extension may then be manually retracted andextended within the outer extendable unit, or may further include aninterconnection with the drive system associated with the existingconveyor.

Therefore, the above embodiment of the present invention provides anadditional outermost boom or extension for a conventional extendableconveyor which does not adversely affect the width of the outermostconveying surface or the height of the conveying surface associated withthe base unit. Because the conveying portion associated with theextendable attachment does not nest within the adjacent extendable unit,the width of the conveying portion may be equal to or greater than theconveying surface associated with the inwardly adjacent extendable unit.Furthermore, because only the support members are nested within theinwardly adjacent adjustable unit, the present invention also does notadversely affect the vertical space required for the inwardly adjacentextendable unit. This further results in a conveyor assembly which hasan uppermost conveying surface along its base unit that is not adverselyaffected by the addition of the extendable attachment, which furtherallows implementation of the present invention without requiringadditional modifications to the conventional supply and/or take-awayconveyor associated with the loading dock or warehouse.

Referring now to FIGS. 8-13, an alternate embodiment of the presentinvention is shown for an extendable conveyor 200. Extendable conveyor200 includes a base unit (not shown, but may be similar to base unit12), and at least one extendable unit 215 which is extendable andretractable relative to the base unit. Extendable conveyor 200 is shownwith two extendable units 224 and 236 and a forward or outer extendableboom 222. The inner or rearward extendable units 215 and the base unitare preferably substantially similar to the extendable units 36, 34, 32,and base 12 described above with respect to extendable conveyor 10.Accordingly, no further discussion of the components and functionalityof these units will be repeated herein.

Outer or forward extendable unit 224 is likewise preferably similar tothe extendable unit 24 discussed above. However, extendable unit 224 ismodified in order to allow extendable boom 222 and its conveying surface226 to nest within outer extendable unit 224. As best shown in FIG. 8,outer extendable unit 224 includes belt rollers 224 a and 224 b atopposite ends thereof and a belt guide roller 224 c positioned forwardlyof roller 224 a. As shown in FIGS. 10 and 11, forward roller 224 b ofextendable unit 224 is rotatably mounted between a pair of brackets 225extending forwardly from a forward cross member 227 secured between sidemembers 254 of extendable unit 224. Belt rollers 224 a and 224 c maylikewise be rotatably mounted between a pair of brackets 229 a extendingforwardly from a rearward cross member 229 b at a rearward end ofextendable unit 224 (FIG. 13). A continuous belt 240 is routed aroundconventional rollers 241 on the inner extendable units and the base unitand around rollers 224 a and 224 b of extendable unit 224, and furtherabout a pair of rollers 280 and 284 on extendable boom 222, such thatproper tension is maintained in the belt regardless of the degree ofextension of the extendable units and boom. The additional guide roller224 c is positioned forwardly or outwardly of inner belt roller 224 a ofextendable boom 224, such that continuous belt 240 is directeddownwardly in front of roller 224 a as it travels toward a forward end224 d of extendable unit 224. This results in belt 240 traveling along alower portion of extendable unit 224 toward forward belt roller 224 b,inorder to provide clearance within extendable unit 224 for retraction ofextendable boom 222 therewithin.

As shown in FIG. 11, side members 254 of forward extendable unit 224 arealso similar to side members 54 of extendable unit 24, discussed above,in that they are substantially C-shaped in cross section. However, alower, inwardly turned portion 254 a of side members 254 includes alaterally inward section 254 b which is preferably upwardly turned suchthat a substantially U-shaped trough or track is formed along lowerportion 254 a of side members 254. Cross members 227 and 229 b areinterconnected between inward sections 254 b on each side 254, in orderto provide clearance within and above track portion 254 a for sidemembers 250 of boom 222, as discussed below. Preferably, side members254 are tapered at their outer end 254 e such that only the U-shapedtrack extends substantially beyond the location of forward roller 224 b.This provides clearance for a control panel 290 on extendable boom 222when extendable boom 222 is fully retracted within forward extendableunit 224, as seen in FIG. 12.

Extendable boom 222 comprises a pair of side members 250 which areinterconnected at their upper ends 250 a such as by an upper conveyingportion 226 which supports conveying belt 240. An inner or rearwardcross member 222 a may extend laterally between side members 250 toprovide lateral rigidity to extendable boom 222 at a rearward end 222 bthereof. A second laterally extending cross beam 222 c may extendbetween side members 250 and may be positioned forwardly of cross member222 a. Rearward conveyor belt roller 280 is rotatably mounted to a pairof brackets 280 a which are fixedly secured along cross member 222 c andextending rearwardly therefrom, as best shown in FIGS. 10 and 13.

At an outer end 222 d of extendable boom 222, a forward or outerconveyor roller 284 is rotatably mounted to a pair of mounting brackets284 a, which extend rearwardly from a forward cross member assembly 290a. One or more control panels 290 may be mounted on either or both sidesof cross member 290 a to allow an operator of extendable conveyor 200 toextend, retract, raise and/or lower the extendable units and extendableboom 222 and to further facilitate operation of conveyor belt 240 fromouter end 222 d of extendable boom 222.

As best shown in FIGS. 9 and 11, rearward belt roller 280 of extendableboom 222 is preferably positioned above the level of belt roller 224 bof extendable unit 224, such that belt 240 is curved in a substantiallyS-shaped curve as it is guided around rollers 224 b and 280. An upperportion of the roller 280 is below conveying surface 226, such thatconveyor belt 240 remains below conveying surface 226 of extendable boom222 as conveyor belt 240 routes around rearward roller 280 towardforward end 222d of extendable boom 222. As belt 240 travels towardforward roller 284, belt 240 is guided slightly downwardly from rearwardroller 280 and reverses direction around forward roller 284. Belt 240then travels rearwardly toward the base unit above and along conveyingsurface 226 of extendable boom 222, the conveying portion or surface 224e of extendable unit 224, and the conveying portions of the inwardlypositioned extendable units, if the respective units are at leastpartially extended from the base unit.

Similar to extendable conveyor 10 discussed above, extendable conveyor200 includes a support system, shown generally at 237 in FIGS. 8, 9 and12, for extendable boom 222. Support system 237 includes a cantileversupport roller 264, which is rotatably mounted at an upper end of a rearor inner mounting bracket 264 a positioned at inner or rearward end 222b of each side member 250 of extendable boom 222. Cantilever supportroller 264 engages a lower surface 254 e of side members 254 asextendable boom 222 is extended from extendable unit 224. As shown inFIGS. 9 and 11, an upper portion 264b of cantilever support roller 264extends upwardly and slightly above a horizontal plane defined by anupper surface 250 e of side members 250, similar to support roller 64 ofextendable boom 22, discussed above. By providing a minimal height abovethe upper surface 250 e of side members 250, extendable boom 222 may beof a desired height for support and durability, without adverselyaffecting the corresponding height requirements for the forwardextendable unit 224.

Support system 237 further includes a support member 223, which ispositioned vertically between side members 250 and the track or channelof lower portion 254 a of side members 254 of extendable unit 224.Support member 223 is preferably a roller carriage 223, which preferablycomprises multiple low profile rollers 223 a, such as the eight rollersshown in FIGS. 8-13. Each of the rollers 223 a includes a center pin 223b (FIG. 11) which may be rotatably interconnected with the other rollers223 a of roller carriage 223. As best shown in FIG. 11, roller carriage223 rests within the U-shaped track along lower portion 254 a of sidemembers 254, such that roller carriage 223 may roll along the length oftrack portion 254 a along side members 254 of extendable unit 224.Roller carriage 223 supports extendable boom 222 as extendable boom 222is extended and retracted within extendable unit 224. A lower surface250 c of each side member 250 maintains rolling contact with each of therollers 223 a of roller carriage 223, while the rollers 223 a furthermaintain rolling contact with an upper surface 254 d of track 254 aalong each side 254. Preferably, each of the rollers 223 a are coatedwith or formed from a rubberized or plastic or other traction enhancingmaterial which freely rolls relative to side members 250 and track 254a, yet substantially precludes slipping between rollers 223 a and eithertrack 254 a or side members 250. Because roller carriage 223 rollsrelative to both extendable unit 224 and extendable boom 222, extendableboom 222 moves outwardly relative to roller carriage 223 as rollercarriage 223 likewise moves outwardly relative to extendable unit 224.Accordingly, roller carriage 223 moves outwardly or forwardly alongtrack 254 a at half the rate at which extendable boom 222 is movedoutwardly therefrom, which results in roller carriage 223 moving halfthe distance that extendable boom 222 may move relative to extendableunit 224. As shown in FIGS. 12 and 13, roller carriage thus ispreferably positioned along track 254 a at approximately a mid point orhalf-way point of extendable unit 224 when extendable boom 222 is fullyretracted therewithin. As extendable boom 222 is extended fromextendable unit 224, roller carriage 223 moves outwardly half thedistance that extendable boom 222 moves, thereby moving substantiallynear to outer end 224 d of extendable unit 224 when extendable boom 222is fully extended therefrom, as shown in FIGS. 9 and 10.

When in its fully retracted position, extendable boom 222 is supportedby and substantially balanced on roller carriage 223, since rollercarriage is preferably positioned at or near the mid point of extendableboom 222. When extendable boom 222 extends outwardly from extendableunit 224, a greater percentage of weight of extendable boom 222 isshifted forwardly of roller carriage 223, such that an upper portion ofcantilever roller 264 engages surface 254 e of extendable unit 224, inorder to cantileverly support extendable boom 222 and prevent downwardmovement of forward end 222 d. Although extendable boom 222 issubstantially balanced on roller carriage 223, it is envisioned thatother support members may be implemented to prevent tilting of boom 222as it is retracted. For example, extendable boom 222 may be furthersupported at rearward or inner end 222 b by cantilever roller 264engaging a flange or track (not shown) on extendable unit 224 whichextends laterally inwardly from sides 254 at a level beneath cantileverroller 264 and engages a lower portion of cantilever roller 264. Aforward cantilever roller (not shown) may alternately be implemented onan upper portion of forward end 222 d of boom 222 to engage surface 254e as extendable boom 222 is retracted within extendable unit 224 to apoint where the majority of the weight shifts rearward of rollercarriage 223. Alternatively, a second, rearward roller carriage (notshown) may also be provided slightly inwardly of the midpoint to supportrearward end 222 b or an inner support roller (not shown) may beprovided on sides 254 to rollingly engage side members 250 as extendableboom 222 is retracted within extendable unit 224. It is furtherenvisioned that roller carriage 223 may include multiple low profilerollers and extend an appropriate length along extendable boom 222 suchthat extendable boom 222 is supported by roller carriage 223 towardrearward end 222 b and thus sufficiently balanced when fully retractedinto forward extendable unit 224.

By positioning a low profile roller carriage 223 vertically betweenlower portion 254 a of side member 254 of extendable unit 224 and lowerportion 250 c of side members 250 of extendable boom 222, the verticalrequirements of extendable unit 224 are minimized, while still allowinga fully nested extendable boom 222 to extend and retract therewithin.Furthermore, the low profile roller carriage 223 may be positionedsubstantially adjacent to or laterally inwardly from a vertical planedefined by side members 250. This allows extendable boom 222 to nestwithin outer extendable unit 224, while minimizing the effect on thewidth of the conveyor surface provided by extendable boom 222 withrespect to the width of the conveying surface of the rest of theextendable conveyor 200. Because the rollers 224 a, 224 c and 224 b ofextendable unit 224 are mounted to a laterally inwardly positionedsection 254 b of sides 254, the mounting brackets and cross members donot interfere with side members 250 of extendable boom 222 as the boomis retracted within unit 224.

Extendable boom 222 may further include a drive motor (not shown) forrotating cantilever support rollers 264, in order to extend and/orretract extendable boom 222 within extendable unit 224, in response toactuation of an appropriate control on control panel 290. Alternatively,however, the drive motor may drive an inner support roller (not shown)or extendable boom 222 may be manually extended and retracted withinextendable unit 224, without affecting the scope of the presentinvention.

Extendable conveyor 200 preferably further includes an electrical cable(not shown) which may be routed through the extendable units in aconventional manner. Preferably, the cable is routed through theextendable units similar to the manner disclosed in the above referencedGilmore '413 patent. In order to provide electrical connections tocontrol panel 290 of extendable boom 222, an electrical cable 292 may berouted and secured along one of the sides 250 of extendable boom 222(FIGS. 11 and 13). The electrical cable 292 is preferably routed withina unidirectionally flexible section of cable track, similar toelectrical cable 92 in extendable conveyor 10, discussed above, suchthat the cable may reverse directions at rearward end 222 b ofextendable boom 222, while the cable remains in its proper lateralorientation along extendable unit 224.

Referring now to FIGS. 14-16, an extendable conveyor 300 may include atleast one extendable unit 315 which is extendable and retractablerelative to a base unit (not shown). Extendable conveyor 300 is shownwith two extendable units 324 and 336 and a forward or outer extendableboom 322. The inner extendable units 315 and the base unit arepreferably substantially similar to the extendable units 36, 34 and 32and the base unit 12, described above with respect to extendableconveyor 10. Accordingly, no further discussion of the components andfunctionality of these units will be repeated herein. Extendable unit324 is substantially similar to extendable unit 224 of conveyor 200,with rollers 324 a, 324 b and 324 c to guide a continuous belt 340.However, extendable unit 324 comprises a pair of opposite side walls354, which are substantially C-shaped and similar to side walls 54 ofextendable unit 24.

Extendable boom 322 comprises a pair of side members 351 which areinterconnected at their upper ends by an upper conveying portion 326which supports conveying belt 340. A pair of opposite support members350 extend along a lower edge 351 a of side members 351 to supportextendable boom 322 as the support members engage at least one supportroller on extendable unit 324. Extendable boom 322 further includes arearward belt roller 380 and a forward belt roller 384, which aregenerally similar to the rollers of extendable boom 222, discussedabove.

Extendable boom 322 further includes a support system 337, whichincludes a cantilever support roller 364 and a forward support roller360, which is rotatably mounted to a bracket 361 at an outer end 354 aof side walls 354 of extendable unit 324. Cantilever support roller 364is rotatably mounted at an inner end 322 a of extendable boom 322,similar to cantilever support roller 264 of extendable boom 222. Aninner support roller 362 may also be rotatably mounted on extendableboom 322 to engage extendable unit 324 and support inner end 322 a ofextendable boom 322 as it is retracted within extendable unit 324,similar to support roller 62 of extendable boom 22.

As best shown in FIG. 16, support roller 360 protrudes laterallyinwardly from bracket 361 and rollingly engages an underside 350 a ofsupport members 350, thereby supporting and guiding extendable boom 322as it extends and retracts within extendable unit 324. Preferably, therollers 360 are positioned directly beneath support members 350. Becauseonly a minimum space is required laterally outwardly from supportmembers 350, this allows support members 350 and extendable boom 322 tonest within extendable unit 324, while being substantially laterallyseparated to provide a wider opening therebetween. This allows greaterclearance between support members 350 for conveyor belt 340, therebyhaving a minimal affect on the range of conveyor belt widths which maybe implemented on conveyor 300. This further facilitates maximizing theratio of the conveyor belt width to the overall width of the extendableconveyor. Inner support roller 362 may be similarly positioned beneathsupport members 350.

As discussed above with respect to extendable booms 22 and 222,extendable boom 322 may further include a control panel (not shown) atan outer end 322 b to allow an operator to extend, retract, raise and/orlower the extendable unit from the outer end of the conveyor. Thecontrol panel may further drive a drive motor to extend or retractextendable boom 322 relative to extendable unit 324. However, extendableboom 322 may otherwise include a handle 323 at its outer end for anoperator to use to manually extend and retract extendable boom 322.

As extendable boom 322 is extended or retracted within extendable unit324, outer support roller 360 rollingly engages underside 350 a ofsupport members 350, while inner support member 362 rollingly engages anupper surface 354 a of a lower inwardly turned portion 354 b of sidemembers 354. As extendable boom 322 extends such that a majority of itsweight is forwardly of outer support roller 360, cantilever rollers 362engage an upper portion 354 c of side members 354 to prevent downwardmovement of outer end 322 b. Clearance is provided within extendableboom for belt 340 and outer roller 324 b of extendable unit 324, suchthat the belt and roller do not interfere with movement of extendableboom 322 along extendable unit 324.

Accordingly, the present invention provides an extendable conveyor whichincludes an outermost extendable boom, which at least partially nestswithin the next inwardly positioned extendable unit. The extendable boomextends and retracts within the next inwardly positioned extendable unitand has a minimal effect on both height and width requirements for thenext inwardly positioned extendable unit, which provides for a greaterwidth of the conveying surface of the extendable boom over conventionalconveyors. The outermost extendable boom is adaptable for extendableconveyors comprising one, two, three, four or more extendable units. Byadding the additional extension, the extendable conveyors may achieve agreater overall length in their extended positions, while minimallyeffecting the floor space requirements for the extendable conveyor whenin their retracted positions and the height of the base unit. Because agreater width conveying surface may be provided on the extendable boomsof the present invention, the ratio of the width of the conveyor belt tothe overall width of the base unit may be maximized.

The present invention further provides an outermost extension which maybe added to an existing two or four unit extendable conveyor withminimal reworking required for the existing extendable conveyor.Accordingly, the additional extension may provide a maximum extendedlength to reach farther into truck trailers, while having no affect onthe required floor space for the unit in its retracted position. Becauseof the minimal affect on the existing conveyor, the additional extensionmay be an aftermarket installation, such that the entire extendableconveyor does not have to be replaced when additional length may becomenecessary.

Changes and modifications in the specifically described embodiments canbe carried out without departing from the principles of the invention,which is intended to be limited only by the scope of the appendedclaims, as interpreted according to the principles of patent law.

The embodiments of the invention in which an exclusive property right orprivilege is claimed are defined as follows:
 1. An extendable conveyorfor conveying articles comprises: a base structure; at least oneextendable unit adjustably positionable between a retracted position andan extended position relative to said base structure, said at least oneextendable unit having an upper portion, which at least partiallydefines a first conveying portion; and an extendable boom at leastpartially nested Akin said at least one extendable unit and adjustablypositionable between a retracted positional and an extended positionrelative to said at least one extendable unit, said extendable bothdefining a second conveying portion, wherein said extendable boomincludes at least one Stever support member which engages said upperportion of said at least one extendable unapantileverly support saidextendable boom relative to said at least one extendable unit when saidextendable boom is at least partially extended relative to said at leastone extendable unit.
 2. The extendable conveyor of claim 1, wherein saidat least one extendable unit is operable to telescopingly extendforwardly such that said at least one extendable unit is cantileverlysupported by one of said base unit and a next most rearwardly positionedextendable unit of said at least one extendable unit, said at least oneextendable unit being cantileverly supported by a cantilever rollerextending downwardly from said at least one extendable unit and engaginga portion of the next most rearwardly positioned extendable unit.
 3. Theextendable conveyor of claim 1 further including a movable continuousconveyor belt which is movable along said first and second conveyingportions.
 4. The extendable conveyor of claim 1, wherein said firstconveying portion has a first width and said second conveying portionhas a second width, said second width being at least as great as saidfirst width.
 5. The extendable conveyor of claim 1, wherein said secondconveying portion is extendable and retractable within said at least oneextendable unit.
 6. The extendable conveyor of claim 5 further includinga movable continuous conveyor belt which is movable along said first andsecond conveying surface portions.
 7. The extendable conveyor of claim 1further including a drive system for extending and retracting said atleast one extendable unit relative to said base structure.
 8. Theextendable conveyor of claim 7, wherein said extendable boom includes acontrol panel positionable at a forward end of said extendable boom,said control panel being operable to control said drive system.
 9. Theextendable conveyor of claim 8, wherein said control panel iselectronically interconnected to a wiring system of said at least oneextendable unit by an electronic cable routed along said extendable boomand within a unidirectionally flexible section of cable track.
 10. Theextendable conveyor of claim 1, further including a support system forsaid extendable boom, said support system including at least one forwardsupport member and said at least one cantilever support member, saidcantilever support member engaging said upper portion of said at leastone extendable unit.
 11. The extendable conveyor of claim 10, whereinsaid forward support member engages and supports said extendable boomand allows a greater width of said second conveying portion relative toa width of said first conveying portion.
 12. The extendable conveyor ofclaim 10, wherein said support system further includes at least onerearward support member positionable near a rearward end of saidextendable boom.
 13. An extendable conveyor including a conveyingsurface for conveying articles and comprising: a base structure; atleast one extendable unit adjustably positionable between a retractedposition and an extended position relative to said base structure, saidat least one extendable unit having a first conveying surface portion;and an extendable boom at least partially nested within said at leastone extendable unit and adjustably positionable between a retractedposition and an extended position relative to said at least oneextendable unit, said extendable boom including a support portion thatcantileverly supports said extendable boom in said at least oneextendable unit, said extendable boom including a second portionpositioned above said support portion and defining a second conveyingsurface portion, said second conveying surface portion beingpositionable at least partially above said first conveying surfaceportion.
 14. The extendable conveyor of claim 13, wherein said secondconveying surface portion has a second width and said first conveyingsurface portion has a first width, said second width being at least asgreat as said first width.
 15. The extendable conveyor of claim 14,wherein said at least one extendable unit is operable to telescopinglyextend outwardly such that said at least one extendable unit iscantileverly supported by said base unit and said at least oneextendable unit.
 16. The extendable conveyor of claim 13, wherein saidextendable boom, said at least one extendable unit and said basestructure share a common endless conveyor belt which travels along saidfirst and second conveying surface portions.
 17. The extendable conveyorof claim 13, further including a drive system for extending andretracting said at least one extendable unit relative to said basestructure.
 18. The extendable conveyor of claim 17, wherein saidextendable boom further includes a control panel positioned at an outerend of said extendable boom, said control panel being electronicallyconnected with said drive system.
 19. The extendable conveyor of claim18, wherein said control panel is connected to an electrical cable whichis routed along said extendable boom within a unidirectionally flexiblesection of cable track, said electrical cable being connected with asecond cable connected with said at least one extendable unit.
 20. Theextendable conveyor of claim 13, further including a support system forsaid extendable boom, said support system comprising at least one outersupport member and at least one cantilever support member.
 21. Theextendable conveyor of claim 20, wherein said cantilever support memberis positioned at an inner end of said support portion, said cantileversupport member engaging an upper portion of said at least one extendableunit.
 22. The extendable conveyor of claim 21, wherein said supportsystem further includes at least one inner support member positionablenear an inner end of said support portion.
 23. An extendable conveyorincluding a conveying surface for conveying articles and comprising: abase structure; at least one extendable unit adjustably positionablebetween a retracted position and an extended position relative to saidbase structure, said at least one extendable unit having a firstconveying surface portion; and an extendable boom at least partiallynested within said at least one extendable unit and adjustablypositionable between a retracted position and an extended positionrelative to said at least one extendable unit, said extendable boomincluding a support portion that cantileverly supports said extendableboom in said at least one extendable unit, said extendable boomincluding a second portion positioned above said support portion anddefining a second conveying surface portion, said second conveyingsurface portion having a second width and said first conveying surfaceportion having a first width, said second width being at least as greatas said first width, wherein said support portion of said extendableboom includes opposite support members which extend and retract withinsaid at least one extendable unit, said second portion beinginterconnected with said support members at an outer end of saidextendable boom.
 24. The extendable conveyor of claim 23, wherein anouter end of said second portion is interconnected with an outer end ofsaid support members such that an inner end of said second portionextends inwardly from said outer end of said support members and ispositioned above at least a portion of said first conveying surfaceportion.
 25. The extendable conveyor of claim 24, wherein said secondportion is pivotally interconnected with said outer end of said supportmembers.
 26. The extendable conveyor of claim 24, wherein saidextendable boom includes a plurality of conveying rollers positionedbetween said inner end of said second portion and said first conveyingsurface portion.
 27. The extendable conveyor of claim 25, wherein saidinner end of said second portion includes a roller for rollingengagement with said first conveying surface portion.
 28. An extendableconveyor for conveying articles comprising: a base structure; at leastone extendable unit adjustably positionable between a retracted positionand an extended position relative to said base structure, said at leastone extendable unit including a first conveying surface portion; anextendable boom which extends and retracts within said at least oneextendable unit, said extendable boom having a second conveying surfaceportion; and a support system for said extendable boom, said supportsystem including at least one inward cantilever support and at least oneoutward roller carriage, said roller carriage including at least oneroller which is operable to roll relative to said at least oneextendable unit and said extendable boom such that said roller carriagemoves outwardly relative to said at least one extendable unit as saidextendable boom moves outwardly relative to said roller carriage andsaid at least one extendable unit, said extendable boom movingapproximately twice the distance that said roller carriage movesrelative to said at least one extendable unit.
 29. The extendableconveyor of claim 28, wherein said at least one extendable unit isoperable to telescopingly extend outwardly such that said at least oneextendable unit is cantileverly supported by one of said base unit and anext most inwardly positioned extendable unit of said at least oneextendable unit.
 30. The extendable conveyor of claim 28, furtherincluding a continuous conveyor belt, said continuous conveyor beltbeing routed around a plurality of rollers in said extendable boom andsaid at least one extendable unit.
 31. The extendable conveyor of claim30, wherein said at least one extendable unit includes first and secondbelt rollers at an inner end thereof and a third belt roller at an outerend thereof, said first and second belt rollers being positioned suchthat said continuous conveyor belt reverses around said first beltroller and is guided downwardly as it travels outwardly toward saidsecond belt roller, such that said continuous conveyor belt travelsalong a lower portion of said at least one extendable unit as it travelstoward said third belt roller, thereby providing clearance within saidat least one extendable unit for retraction of said extendable boomtherewithin.
 32. The extendable conveyor of claim 28, wherein saidextendable boom includes a control panel positionable at an outer end ofsaid extendable boom, said control panel being operable to control adrive system for extending and retracting said at least one extendableunit relative to said base structure.
 33. The extendable conveyor ofclaim 32, wherein said control panel is electronically connected to awiring system of said at least one extendable unit by an electroniccable routed along said extendable boom and within a unidirectionallyflexible section of cable track.
 34. The extendable conveyor of claim28, wherein said extendable boom has a pair of opposite side members,said roller carriage rollingly engaging each of said side members ofsaid extendable boom and a lower portion of said at least one extendableunit.
 35. The extendable conveyor of claim 34, wherein at least aportion of said roller carriage is positioned beneath said side memberlaterally inwardly adjacent to a vertical plane defined by said sidemember to allow a reduced range in widths of said extendable boom andsaid at least one extendable unit and thereby a greater width of saidsecond conveying surface portion relative to the width of said firstconveying surface portion.
 36. The extendable conveyor of claim 34,wherein said second conveying surface portion is interconnected along anupper portion of said side members of said extendable boom, said secondconveying surface portion extending and retracting within said at leastone extendable unit.
 37. The extendable conveyor of claim 34, whereinsaid at least one extendable unit includes a pair of sidewalls whichfurther include a generally horizontal track protruding laterallyinwardly along said lower portion of said at least one extendable unit,said roller carriage being operable to roll along said track when saidextendable boom is extended and retracted relative to said at least oneextendable unit.
 38. The extendable conveyor of claim 37, wherein saidcantilever support member is positioned at an inner end of said sidemembers, said cantilever support member extending at least partiallyabove an upper surface of said side members to engage an upper structureof said at least one extendable unit, said cantilever support memberbeing vertically adjacent to a horizontal plane defined by said uppersurface of said side members to allow a reduced range in height of saidat least one extendable unit.
 39. An extendable conveyor for conveyingarticles comprises: a base structure; at least one extendable unitadjustably positionable between a retracted position and an extendedposition relative to said base structure, said at least one extendableunit having an upper portion, which at least partially defines a firstconveying portion; and an extendable boom at least partially nestedwithin said at least one extendable unit and adjustably positionablebetween a retracted position and an extended position relative to saidat least one extendable unit, said extendable boom defining a secondconveying portion, wherein said extendable boom engages said upperportion of said at least one extendable unit to cantileverly supportsaid extendable boom relative to said at least one extendable unit whensaid extendable boom is at least partially extended relative to said atleast one extendable unit. wherein said extendable boom comprises saidsecond conveying portion and a support portion, a forward end of saidsecond conveying portion being interconnected to a forward end of saidsupport portion and extending rearwardly therefrom and vertically aboveat least a portion of said first conveying portion of said at least oneextendable unit.
 40. The extendable conveyor of claim 39, wherein saidforward end of said second conveying portion is pivotally interconnectedwith said forward end of said support portion.
 41. The extendableconveyor of claim 40, wherein a rearward end of said second conveyingportion includes a support roller for rolling engagement with said firstconveying portion.
 42. The extendable conveyor of claim 41, wherein saidextendable boom includes a plurality of conveying rollers positionablebetween said rearward end of said second conveying portion and saidfirst conveying portion.
 43. An extendable conveyor for conveyingarticles comprises: a base structure; at least one extendable unitadjustably positionable between a retracted position and an extendedposition relative to said base structure, said at least one extendableunit having an upper portion, which at least partially defines a firstconveying portion; and an extendable boom at least partially nestedwithin said at least one extendable unit and adjustably positionablebetween a retracted position and an extended position relative to saidat least one extendable unit, said extendable boom defining a secondconveying portion, wherein said extendable boom engages said upperportion of said at least one extendable unit to cantileverly supportsaid extendable boom relative to said at least one extendable unit whensaid extendable boom is at least partially extended relative to said atleast one extendable unit; and a support system for said extendableboom, said support system including at least one forward support memberand at least one cantilever support member, said cantilever supportmember engaging said upper portion of said at least one extendable unit,wherein said forward support member comprises a plurality of low profilerollers which rollingly engage both said extendable boom and said atleast one extendable unit.
 44. The extendable conveyor of claim 43,wherein said at least one extendable unit includes a pair of sidewallswhich further include a generally horizontal track protruding laterallyinwardly along a lower portion of said sidewalls, said forward supportmember being operable to roll along said track when said extendable boomis extended and retracted relative to said at least one extendable unit.45. The extendable conveyor of claim 44, wherein said forward supportmember rolls forwardly along said track as said extendable boom isextended such that said extendable boom moves approximately twice thedistance that said forward support member moves relative to said atleast one extendable unit.
 46. The extendable conveyor of claim 44,wherein said extendable boom includes a pair of opposite side members,said second conveying surface being interconnected along an upper edgeof said side members, said second conveying surface extending andretracting within said at least one extendable unit while said forwardsupport member rollingly engages said track and a lower surface of saidside members.
 47. An extendable conveyor for conveying articlescomprises: a base structure; at least one extendable unit adjustablypositionable between a retracted position and an extended positionrelative to said base structure, said at least one extendable unithaving an upper portion, which at least partially defines a firstconveying portion; an extendable boom at least partially nested withinsaid at least one extendable unit and adjustably positionable between aretracted position and an extended position relative to said at leastone extendable unit, said extendable boom defining a second conveyingportion, wherein said extendable boom engages said upper portion of saidat least one extendable unit to cantileverly support said extendableboom relative to said at least one extendable unit when said extendableboom is at least partially extended relative to said at least oneextendable unit; a support system for said extendable boom, said supportsystem including at least one forward support member and at least onecantilever support member, said cantilever support member engaging saidupper portion of said at least one extendable unit, said support systemincluding at least one rearward support member positionable near arearward end of said extendable boom; and a drive system for extendingand retracting said extendable boom relative to said at least oneextendable unit, said drive system driving one of said support membersof said support system.
 48. An extendable conveyor for conveyingarticles comprises: a base structure; at least one extendable unitadjustably positionable between a retracted position and an extendedposition relative to said base structure, said at least one extendableunit having an upper portion, which at least partially defines a firstconveying portion; and an extendable boom at least partially nestedwithin said at least one extendable unit and adjustably positionablebetween a retracted position and an extended position relative to saidat least one extendable unit, said extendable boom defining a secondconveying portion, wherein said extendable boom engages said upperportion of said at least one extendable unit to cantileverly supportsaid extendable boom relative to said at least one extendable unit whensaid extendable boom is at least partially extended relative to said atleast one extendable unit; a drive system for extending and retractingsaid at least one extendable unit relative to said base structure; and asecond drive system for extending and retracting said extendable boomrelative to said at least one extendable unit.
 49. An extendableconveyor for conveying articles comprises: a base structure; at leastone extendable unit adjustably positionable between a retracted positionand an extended position relative to said base structure, said at leastone extendable unit having an upper portion, which at least partiallydefines a first conveying portion; an extendable boom at least partiallynested within said at least one extendable unit and adjustablypositionable between a retracted position and an extended positionrelative to said at least one extendable unit, said extendable boomdefining a second conveying portion, wherein said extendable boomengages said upper portion of said at least one extendable unit tocantileverly support said extendable boom relative to said at least oneextendable unit when said extendable boom is at least partially extendedrelative to said at least one extendable unit; and a first movablecontinuous conveyor belt which is movable along said first conveyingportion and a second movable continuous conveyor belt which is movablealong said second conveying portion.
 50. An extendable conveyorincluding a conveying surface for conveying articles and comprising: abase structure; at least one extendable unit adjustably positionablebetween a retracted position and an extended position relative to saidbase structure, said at least one extendable unit having a firstconveying surface portion; and an extendable boom at least partiallynested within said at least one extendable unit and adjustablypositionable between a retracted position and an extended positionrelative to said at least one extendable unit, said extendable boomincluding a support portion that cantileverly supports said extendableboom in said at least one extendable unit, said extendable boomincluding a second portion positioned above said support portion anddefining a second conveying surface portion, wherein said at least oneextendable unit and said base structure include a first endless conveyorbelt which travels along said first conveying surface portion and saidextendable boom includes a second endless conveyor belt which travelsalong said second conveying surface portion.
 51. An extendable conveyorincluding a conveying surface for conveying articles and comprising: abase structure; at least one extendable unit adjustably positionablebetween a retracted position and an extended position relative to saidbase structure, said at least one extendable unit having a firstconveying surface portion; an extendable boom at least partially nestedwithin said at least one extendable unit and adjustably positionablebetween a retracted position and an extended position relative to saidat least one extendable unit, said extendable boom including a supportportion that cantileverly supports said extendable boom in said at leastone extendable unit, said extendable boom including a second portionpositioned above said support portion and defining a second conveyingsurface portion; and a drive system for extending and retracting said atleast one extendable unit relative to said base structure, wherein saidextendable boom is extendable by said drive system at a rate which istwice a rate that said drive system extends an outermost unit of said atleast one extendable unit.
 52. An extendable conveyor including aconveying surface for conveying articles and comprising: a basestructure; at least one extendable unit adjustably positionable betweena retracted position and an extended position relative to said basestructure, said at least one extendable unit having a first conveyingsurface portion; a drive system for extending and retracting said atleast one extendable unit relative to said base structure; and anextendable boom at least partially nested within said at least oneextendable unit and adjustably positionable between a retracted positionand an extended position relative to said at least one extendable unit,said extendable boom including a support portion that cantileverlysupports said extendable boom in said at least one extendable unit, saidextendable boom including a second portion positioned above said supportportion and defining a second conveying surface portion, wherein saidextendable boom includes a second drive system for extending andretracting said extendable boom relative to said at least one extendableunit.
 53. An extendable conveyor including a conveying surface forconveying articles and comprising: a base structure; at least oneextendable unit adjustably positionable between a retracted position andan extended position relative to said base structure, said at least oneextendable unit having a first conveying surface portion; an extendableboom at least partially nested within said at least one extendable unitand adjustably positionable between a retracted position and an extendedposition relative to said at least one extendable unit, said extendableboom including a support portion that cantileverly supports saidextendable boom in said at least one extendable unit, said extendableboom including a second portion positioned above said support portionand defining a second conveying surface portion; a support system forsaid extendable boom, said support system comprising at least one outersupport member and at least one cantilever support member, saidcantilever support member being positioned at an inner end of saidsupport portion, said cantilever support member engaging an upperportion of said at least one extendable unit, said support systemfurther including at least one inner support member positionable near aninner end of said support portion; and a drive system for extending andretracting said extendable boom relative to said outer extendable unit,said drive system driving at least one of said support members of saidsupport system.